Yes. Several commercial planter manufacturers offer urban planter box models with locking casters, and these are increasingly used where planters need to be movable for maintenance but secure in daily use. The key is to specify the right caster and locking system rather than assuming that any wheeled planter is secure.
For security-focused projects, look for total-lock casters that lock both the wheel and the swivel, ideally with a brake on every caster. Heavy-duty polyurethane or rubber wheels, sealed bearings, reinforced mounting plates, and tamper-resistant hardware help the planter handle outdoor use and resist forced movement. Some models also offer keyed caster locks, removable casters, or recessed release mechanisms so staff can unlock and reposition the planter while the public cannot easily roll it away.
Material and weight matter too. Powder-coated steel, aluminum, concrete composite, or ballasted HDPE planter boxes add stability, while integrated drainage and a raised base protect the casters and plants. For higher-risk locations, pair locking casters with ground anchors, cable locks, or fixed bases, and confirm that the caster load rating matches the planter’s filled weight.
In short, locking-caster urban planter boxes are available, but security depends on the full system: total-lock brakes, robust casters, tamper-resistant controls, appropriate weight, and optional anchoring. Ask suppliers for load ratings, lock type, replacement parts, and tested security features before specifying.